There are various online docs about using IContainer and ISite (eg http://www.theserverside.net/tt/blogs/showblog.tss?id=pluginArchitectures), and there are vague examples around, but I haven't come across a real instance (other than winforms) where it is actually useful. It doesn't help that I don't really know what exactly it can be used for. Has anyone use the .NET container interfaces & corresponding classes in their own code, independantly of winforms, and how have you used them?
A:
These the component oriented elements of a component oriented approach to software. The visual designer, for example, uses them.
If you wish to build reusable software components (IComponent), and have the ability to adapt (ISite) the component in various domains as a canonical assembly (IContainer), specially in context of a design-time/run-time framework (visualstudio) then there you are ...